Marilyn Fox Rutherford (nee Marilyn Louise Fox) was born Nov. 12, 1928, in Emlenton, a small town on the Allegheny River halfway between Pittsburgh and Erie. Her father, Clarence Jennings Fox, was a certified public accountant and the nephew of H.J. Crawford, a pioneer in the oil industry and the president of three local banks. Her great-grandfather, Josiah B. Fox ,was a Lutheran minister who founded the local Lutheran church and established the first secondary school in the area. Marilyn's mother, Mabel Viola Lynn, was the daughter of Daniel Marqua Lynn, a local carpenter and farmer. Marilyn grew up in a big house on a steep hill, three blocks from Emlenton's downtown with its one traffic light. Marilyn had three siblings: John (Jack) Lynn Fox, her older brother, George Edwin Fox, her younger brother, and Nancy Jane Fox, her younger sister. Her childhood companions included Pete, a rambunctious Irish Setter, and Fluffy, her pet chicken, who followed her around like a dog. Marilyn was an excellent student, and she graduated from Emlenton High near the top of her class of six. She was also a talented drum majorette. She went on to win the Pennsylvania State Championship in baton twirling.
Marilyn began her bachelor's degree at Grove City College, where she joined Sigma Delta Phi, although she also took summer classes at Temple University and the University of California, Los Angeles. During her junior year, she transferred to the University of Wisconsin, where she studied psychology under Harry Harlow, who was famous for his research using baby rhesus monkeys to study the effects of maternal bonding. At the University of Wisconsin, she joined Kappa Kappa Gamma, where her sorority sisters included the movie star, Gena Rowlands. Another sorority sister convinced her to spend a summer in New York City, where Marilyn worked as an elevator operator before taking a job as a jingle judge for an (advertising) firm running a contest. Back in Madison, Marilyn won a spot on the water ballet team and was voted "the most athletic coed not majoring in P.E."